<- Industry type w/ kickass employee discount. nyaah nyaah...
Online vendors I regularly plug include
www.pc-pitstop.com, who tends to value quality over selection, and has decent prices. the BEST place for SCSI adapters/cables.
www.centrix-intl.com which is a surplus vendor
www.hitechcafe.com, surplus/refurb specialists who occasionally have new stuff.
www.netseller.com but I wouldn't buy a mobo from them as they only carry brands that I don't respect.